Mathew Ingram (mathewi) said: "WhatsApp undergoes some downtime, as founders are too busy counting out their Facebook billions one bill at a time".

Professional footballer Febian Brandy (FebianBrandy) tweeted: "Facebook and WhatsApp toying with our emotions we need to send messages you know. hurry up and sort yourselves out and get the deal done".

Tom Osborne (youngstapreneur) said: "Thought Facebook was leaving WhatsApp alone. Apart from maybe shifting it to their servers! Been down for an hour".

Facebook announced on Thursday that its deal with WhatsApp comprised $4 billion (£2.4 billion) in cash and $12 billion (£7.18 billion) worth of Facebook shares.

Around 70% of WhatsApp's monthly 450 million users use the application every day, Facebook said.

Speaking about his firm's latest acquisition, founder and chief executive of Facebook Mark Zuckerberg said: "WhatsApp is on a path to connect one billion people. The services that reach that milestone are all incredibly valuable."